I wouldn’t plan on relying on poseable symmetry. It’s great within certain applications, but can easily be broken depending on what you do with the subject. For instance it would require you to keep mirror topology, denying you the use of many convenient zbrush features.
Besides, the whole point to someone choosing to pose first early on and then sculpt would be to do without “cheats” like automatic symmetry, to produce a more naturalistic and less predictable sculpt, like a traditional sculptor would produce, or for the purposes of developing skill.
If you are worried about efficiency or not confident in your ability to work without auto symmetry, there’s no reason to work without it. For static poses, the vast majority of digital artists sculpt a figure in a neutral position with symmetry to some degree, pose, and then do a pass without symmetry to refine the form and put in details. Exactly which stage they choose to do which varies by artist preference.